Conventionally, disclosed is a radar device that emits a frequency-modulated transmission signal to a target object, and measures a distance to the target object based on a beat signal generated by mixing its reflected wave and the transmission signal (see Patent Literature 1).
Further, all objects with a temperature naturally emits infrared, and an object emits, as having a higher temperature, infrared stronger. As a result, known is an infrared thermometer in which when infrared emitted from a target object is received and intensity of the received infrared is analyzed, a temperature of the target object is measured.
FIG. 9 illustrates a conventional measuring device that collectively has functions for measuring a distance to a target object and a temperature of the target object.
The conventional measuring device includes a transmitting and receiving antenna 901, a circulator unit 902, a reception signal amplifying unit 903, a frequency converting unit 904, a beat signal amplifying unit 905, a signal processing unit 906, a frequency modulation signal generating unit 908, a high-frequency signal generating unit 909, a high-frequency signal branching unit 910, a transmission signal amplifying unit 912, an infrared light receiving lens 914, and an infrared thermometer 915.
In the conventional measuring device, a high-frequency signal generated from the high-frequency signal generating unit 909 is frequency-modulated by a control voltage produced from the frequency modulation signal generating unit 908 under the control of the signal processing unit 906, and is output as a transmission signal.
FIG. 10 is schematic diagrams of control using a control voltage of the conventional measuring device. FIG. 10(a) illustrates an outline of the control voltage in the frequency modulation signal generating unit 908, and FIG. 10(b) illustrates an outline of frequency in the high-frequency signal generating unit 909. As illustrated in FIG. 10(a), the control voltage produced from the frequency modulation signal generating unit 908 under the control of the signal processing unit 906 changes from a voltage V1 to V2 during the time T1 to repeat this change in each time T1. Then, as illustrated in FIG. 10(b), according to a change in the control voltage of the frequency modulation signal generating unit 908, a high-frequency signal generated in the high-frequency signal generating unit 909 changes from a frequency F1 to F2 during the time T1 to repeat this change in each time T1. As described above, from the high-frequency signal generating unit 909, the transmission signal frequency-modulated by the control voltage from the frequency modulation signal generating unit 908 is continuously supplied to the high-frequency signal branching unit 910.
Returning to FIG. 9, the transmission signal produced from the high-frequency signal generating unit 909 is branched by the high-frequency signal branching unit 910, power-amplified by the transmission signal amplifying unit 912, and emitted toward the target object 913 from the transmitting and receiving antenna 901 via the circulator unit 902.
Due to the emission of the transmission signal, reflected waves from the target object 913 is input to the transmitting and receiving antenna 901. The reflected waves from the target object 913 is produced from the transmitting and receiving antenna 901 as the reception signal. The reception signal is amplified by the reception signal amplifying unit 903 via the circulator unit 902 and is supplied to the frequency converting unit 904. In the frequency converting unit 904, the transmission signal branched by the high-frequency signal branching unit 910 and the reception signal are mixed, and a beat signal is supplied to the beat signal amplifying unit 905. The supplied beat signal is amplified by the beat signal amplifying unit 905, and is supplied to the signal processing unit 906. The signal processing unit 906 calculates a distance to the target object based on the beat signal.
On the other hand, infrared emitted from the target object 913 is received by the infrared light receiving lens 914 and is supplied to the infrared thermometer 915. The infrared thermometer 915 analyzes intensity of the infrared and supplies the analyzed signal to the signal processing unit 906. The signal processing unit 906 finds a temperature distribution of the target object 913 based on the analyzed signal, and calculates the temperature of the target object 913 from its average.